1. Technical Field
The present invention relates to an aqueous ink composition, an ink jet recording method, and a recorded material.
2. Related Art
For recording on an ink-non-absorbent recording medium such as plastic films, non-aqueous ink compositions containing an organic solvent as a matrix have been conventionally used from the viewpoint of quick drying and preventing ink bleeding. On the other hand, aqueous ink compositions containing water as a solvent have been used in consideration of global environment and safety.
For an aqueous ink composition containing a yellow pigment as a color material, C. I. Pigment Yellow 74 may be used as the yellow pigment. However, C. I. Pigment Yellow 74 has insufficient light fastness. In order to enhance the light fastness, it has been suggested that C. I. Pigment Yellow 180 be substituted for C. I. Pigment Yellow 74.
Unfortunately, an aqueous ink composition containing C. I. Pigment Yellow 180 may be inferior in storage stability at low temperatures. When it is frozen by being stored at a low temperature of −10° C. or less and is then thawed out, the pigment may be aggregated. For example, JP-A-2005-60411, JP-A-2005-60419 and JP-A-2007-154087 disclose that a moisturizing component such as glycerol is added to prevent the aqueous ink composition containing a yellow pigment from freezing. Some aqueous ink compositions containing a yellow pigment can have their low-temperature storage stability improved by adding glycerol or the like.
When an aqueous ink composition containing a yellow pigment is used to form an image on a plastic recording medium or the like, the composition comes into contact with other colors. This may cause bleeding in the image, resulting in a poor image. It is known that alkanediol or the like may be added to the aqueous ink composition to reduce the bleeding.
For example, JP-A-2007-154087 discloses that an aqueous ink composition containing 1,2-hexanediol or the like can form good uniform images in some cases of image recording.
However, if a moisturizing component such as glycerol is added to an aqueous ink composition containing C. I. Pigment Yellow 180, the aqueous ink composition may degrade the rub-fastness of the image formed on a plastic recording medium or the like, and good images may not be formed.
Also, if alkanediol or the like is added to an aqueous ink composition containing C. I. Pigment Yellow 180, the low-temperature storage stability of the aqueous ink composition may be degraded.